1. Field of the Invention
The present invention relates in general to a mover vibration absorbing device for a linear motor elevator and, more particularly, to a structural improvement in a vibration absorbing rubber of the device for reliably absorbing the operational vibration generated when an elevator car is accelerated or decelerated abruptly.
2. Description of the Prior Art
With reference to FIG. 1, there is shown in a perspective view a linear motor elevator having a typical mover vibration absorbing device. As shown in this drawing, the elevator includes a pair of horizontal support shafts 1 whose opposite ends are fixed to a pair of side support frames 2 so that the shafts 1 are arranged in parallel and spaced out at an interval. Each of the support shafts 1 is provided with a pair of rotatable pulleys 3. Two ropes 5 are wrapped about the pulleys 3 so that each rope 5 is commonly wrapped about one of the pulleys 3 of the first shaft 1 and about one of the pulleys 3 of the second shaft 1. One end of each of the ropes 5 is commonly connected to an elevator car 4, while the other end of each of the ropes 5 is commonly connected to a counter support unit 20.
The counter support unit 20 which is commonly connected to the other ends of the ropes 5 is a right-angled hexahedral unit whose front and rear walls open to the front and to the back respectively. The unit 20 is provided with a linear motor stator 6 of the rod type, which motor stator 6 vertically penetrates the right-angled hexahedral unit 20. The top end of the vertically arranged stator 6 is fixed to the center of the bottom surface of a top support frame 2a, while the bottom end of the stator 6 is fixed to the center of a bottom support frame 8. A hollow cylindrical mover 7 of the linear motor is fixedly placed in the center of the counter support unit 20. The stator 6 vertically penetrates the mover 7, so that the mover 7 vertically rectilinearly reciprocates while sliding on the vertically arranged stator 6.
Vertically placed in the opposed sides of the counter support unit 20 having the mover 7 is a pair of first guide rails 9. The first guide rails 9, which are adapted for guiding the vertical reciprocation of counter support unit 20 driven by the linear motor, are parallel with and spaced from the stator 6 at the same interval. In order to guide the vertical reciprocation of the elevator car 4, a pair of second guide rails 9a are vertically placed in the opposed sides of the car 4.
If described in detail the counter support unit 20 in conjunction with FIGS. 2A, 2B and 3, the bottom section and the top section of the mover 7 fixedly placed in the center of the unit 20 are connected to top and bottom frames 21 and 22 respectively. The top and bottom frames 21 and 22, which in turn are connected to the top and bottom surfaces of the unit 20, are lengthwise slitted in their centers so as to become hollow frames. The interiors of the top and bottom frames 21 and 22 are hollowed, so that they make their engagement with hollow ring type top and bottom vibration absorbing rubbers 30 and 40 more firmly. The counter support unit 20 is also provided with auxiliary supports 23 which are engaged with the interior sides of the unit 20. The width of the auxiliary supports 23 is slightly smaller than the width of the counter support unit 20.
In the above elevator, the top surface of the mover 7 may severely collide on a flange 21a of the top frame 21 and generate a severe mechanical vibration when the elevator car 4 is accelerated or decelerated abruptly. In order to absorb the collision vibration, the elevator includes a vibration absorbing device. The vibration absorbing device comprises a top vibration absorbing unit 50 which includes the flange 21a of the top frame 21, a top support member 31 and the plurality of top vibration absorbing rubbers 30.
In the same manner, the bottom surface of the mover 7 may severely collide on a flange 22a of the bottom frame 22 and generate a severe mechanical vibration when the elevator car 4 is accelerated or decelerated abruptly. In order to absorb the collision vibration, the elevator also includes a bottom vibration absorbing unit 51 which comprises the flange 22a of the bottom frame 22, a bottom support member 41 and the plurality of bottom vibration absorbing rubbers 40. The top and bottom vibration absorbing units 50 and 51 constitute the typical vibration absorbing device.
Hereinbelow, the constructions of the top and bottom vibration absorbing units 50 and 51 of the device will be described in more detail.
In the top vibration absorbing unit 50, the hollow cylindrical top support member 31 is mounted on the top surface of the hollow cylindrical mover 7 as shown in FIG. 3. Four vibration absorbing rubbers or the top vibration absorbing rubbers 30 are placed in the space between the flange 21a of the top frame 21 and a flange 31a of the top support member 31, so that the four top rubbers 30 are spaced out at 90.degree. angles. In order to assemble the elements into the top vibration absorbing unit 50, a plurality of first bolts 32 upwardly penetrate the flange 31a of the top support member 31, their associated hollow ring type top vibration absorbing rubbers 30 and the flange 21a of the top frame 21. The first bolts 32 in turn are tightly engaged with their associated first nuts 33 on the top surface of the flange 21a of the top frame 21.
In the bottom vibration absorbing unit 51, the hollow cylindrical bottom support member 41 is mounted on the bottom surface of the hollow cylindrical mover 7 as shown in FIG. 3. Four vibration absorbing rubbers or the bottom vibration absorbing rubbers 40 are placed in the space between the flange 22a of the bottom frame 22 and a flange 41a of the bottom support member 41, so that the four bottom rubbers 40 are spaced out at 90.degree. angles. In order to assemble the elements into the bottom vibration absorbing unit 51, a plurality of second bolts 42 downwardly penetrate the flange 41a of the bottom support member 41, their associated hollow ring type bottom vibration absorbing rubbers 40 and the flange 22a of the bottom frame 22. The second bolts 42 in turn are tightly engaged with their associated second nuts 43 on the bottom surface of the flange 22a of the bottom frame 22.
In operation of the above linear motor elevator, the mover 7 is applied with electric power, so that the linear motor is started. A conductive magnetic field is thus generated between the stator 6 and the mover 7 of the linear motor, thus to make the mover 7 together with the counter support unit 20 vertically move upward or downward along the vertically arranged stator 6 under the guide of the first guide rails 9. Therefore, the elevator car 4 which cooperates with the counter support unit 20 vertically moves downward or upward under the guide of the second guide rails 9a.
In the vertical reciprocating motion of the elevator car 4 of the above linear motor elevator, the mechanical vibration caused by collision of the top and bottom surfaces of the mover 7 on the top and bottom frames 21 and 22 when the elevator car 4 is accelerated or decelerated abruptly is absorbed by the top and bottom vibration absorbing rubbers 30 and 40. That is, the impact which is generated in both the flange 21a of the top frame 21 and the flange 31a of the top support member 31 due to collision of the top surface of the mover 7 on the top frame 21 is absorbed by the top vibration absorbing unit 50. In the top vibration unit 50, the flange 31a of the top frame 31 moves upward under the guide of the threadless shank sections of the first bolts 32 penetrating the ring type top vibration absorbing rubbers 30, thus to compress the rubbers 30 and to make the rubbers 30 absorb the collision impact.
In the same manner, the impact which is generated in both the flange 22a of the bottom frame 22 and the flange 41a of the bottom support member 41 due to collision of the bottom surface of the mover 7 on the bottom frame 22 is absorbed by the bottom vibration absorbing unit 51. In the bottom vibration unit 51, the flange 41a of the bottom frame 41 moves downwardly under the guide of the threadless shank sections of the second bolts 42 penetrating the ring type bottom vibration absorbing rubbers 40, thus to compress the rubbers 40 and to make the rubbers 40 absorb the collision vibration.
However, in the typical vibration absorbing device, the bottom vibration absorbing rubbers 40 are directly applied with weight of the mover 7 when the elevator car 4 is stopped. The bottom vibration absorbing rubbers 40 are thus always compressed by the weight of the mover 7 during stop of the elevator car 4. In this regard, the elastic restoring forces of the bottom vibration absorbing rubbers 40 will be more reduced than the elastic restoring forces of the top vibration absorbing rubbers 30 after lapse of predetermined time.
As described above, the typical vibration absorbing device for the linear motor elevator is designed so that the bottom vibration absorbing rubbers are directly applied with the compression force of the mover of the linear motor. Hence, the vibration absorbing device has a problem that the elastic restoring forces of the bottom vibration absorbing rubbers are more reduced than the elastic restoring forces of the top vibration absorbing rubbers. Furthermore, in the top vibration absorbing unit of the device, gaps will be formed between the bottom surface of the flange of the top frame and the top surfaces of the top vibration absorbing rubbers as well as between the top surface of the flange of the top support member and the bottom surfaces of the top vibration absorbing rubbers due to the weight of the mover after lapse of predetermined time. With the gaps, the top frame is separated from the mover, so that the mover fails in coming into even contact with the top vibration absorbing rubbers whenever the mover of the linear motor is started or stopped. This causes uneven abrasion of the top vibration absorbing rubbers and generates vibration of the counter support unit and vibration of the elevator car.